Fun Sun Stuff

Discussion in 'Off Topic Chat' started by KmH, Sep 22, 2017.

  1. KmH

    KmH Helping photographers learn to fish Supporting Member

    Joined:
    Apr 9, 2009
    Messages:
    40,330
    Likes Received:
    5,506
    Location:
    Iowa
    Can others edit my Photos:
    Photos OK to edit
    If there was a way to re-fuel a commercial airliner in flight it would take one about 45 hours to fly around Earth at the equator.
    It would take the same airliner about 6.3 months to fly around the Sun. The Sun is extremely close to being a perfect sphere and is not anywhere near as oblate as Earth so it wouldn't matter if you didn't fly around the Sun's equator.

    As photographers we know the Sun's surface temperature (color - for white balance purposes) is about 5800° K .
    The temperature of the Sun's core is some 15,700,000° K.

    Each second the Sun 'burns' (actually fuses via the proton-proton chain) some 620 metric tons of hydrogen, into some 616 metric tons of helium 'ash', which produces some 4.3 metric tons of radiation (E=mc²) that is mostly light (photons).

    However that 'mostly light (photons)' is pretty much all x-rays (0.01 to 10 nanometers). The x-rays work their way from the core to the surface of the Sun (a process that takes several million years) they diffuse and cool and at the surface are then some 50% infrared photons (light), 40% visible photons (light - 400 to 700 nanometers), and 10% UV photons (light).

    The Sun's core is 20% to 25% of the Sun’s size. Core density is some 150 times the density of water.
    They recently determined the core rotates once every 4 days or so.

    Viewed from Earth's equator (synodic) the apparent rotational period of the Sun at its equator is about 26.25 days, about 35 days at the Sun's poles. Relative to the stars (sidereal) the rotational period of the Sun at its equator is 24.5 days and 33.5 days at the poles.

    99% of the Sun's power is generated within 24% of the Sun's radius, and by 30% of the radius, nuclear fusion has essentially stopped.

    In 5.5 billion years the Sun will be twice as luminous as it is now and will be at the end of that part of it's life it has spent as a Main Sequence star.
    Over the next 500,000,000 years the Sun will double in size as it burns hydrogen in a shell around an inert helium core.
    It will then expand more rapidly over the next half a billion years until it is over 200x larger than today and a couple of thousand times more luminous.

    The Sun will then spend about 1 billion years as a red giant and will spew about 1/3 of it's mass away in a powerful solar wind. As a red giant the Sun's surface temperature will have dropped to about 3500° K.

    When the red-giant phase ends the Sun has approximately 120 million years of active life left, but some pretty spectacular stuff is going to happen over the 120 million years.

    First, that inert core of helium gets hot enough (6x hotter than the sun's core is now) to ignite violently in what is called a helium flash (triple-alpha process), where it is estimated that 6% of the core (itself 40% of the Sun's mass) will be converted into carbon within a matter of minutes.
    Because of the helium flash the Sun will shrink from 200x larger to around 10x its current size and 50 times the luminosity. It's surface will heat back up to a surface temperature a little lower than today.

    The sun will become moderately larger and more luminous over about 100 million years as it continues to burn helium in the core.

    When the helium in the core is exhausted, the Sun will repeat the expansion it did when the hydrogen in the core was exhausted, except that this time it all happens faster. Once again the Sun becomes larger and more luminous.
    The Sun will then be alternately burning hydrogen in a shell or helium in a deeper shell around the new carbon core made during the helium flash. The carbon is inert, not hot enough to fuse.

    After about 20 million years the Sun becomes increasingly unstable, with rapid mass loss and thermal pulses that increase the size and luminosity of the Sun for a few hundred years every 100,000 years or so.
    The thermal pulses become larger each time, with the later pulses pushing the luminosity to as much as 5,000 times the current level and the radius to over 1 AU (1 AU is the radius of Earth's orbit).

    The process speeds up again and the Sun begins rapidly ejecting mass.
    The luminosity stays approximately constant as the temperature increases, with the ejected half of the Sun's mass becoming ionized into a planetary nebula as the now exposed core reaches 30,000 K. The core no longer has any active nuclear processes and is pretty much just carbon.

    The final naked core, called a white dwarf, will have a surface temperature of over 100,000 K, and contain an estimated 54.05% of the Sun's present day mass.
    The planetary nebula will be visible for some 10,000 years before it disperses, but the white dwarf core will survive for trillions of years before fading to a hypothetical black dwarf.
    Note: the oldest any star can be is some 13.3 billion years, so no star is anywhere old enough to have become a black dwarf.

    Somewhat more than 97% of all the stars in the universe will become white dwarfs.


     
    Last edited: Sep 22, 2017
  2. jaomul

    jaomul Been spending a lot of time on here!

    Joined:
    Feb 4, 2011
    Messages:
    5,413
    Likes Received:
    1,414
    Location:
    Cork Ireland
    Can others edit my Photos:
    Photos OK to edit
    I think camera tech will be good enough by then to sort the correct WB for each phase

    Seriously though, that's fascinating and makes me feel a bit unimportant
     
    • Funny Funny x 1
  3. Designer

    Designer Been spending a lot of time on here!

    Joined:
    Apr 13, 2012
    Messages:
    16,061
    Likes Received:
    4,018
    Location:
    Iowa
    Can others edit my Photos:
    Photos OK to edit
    That is so sad. :frown-new:
     
  4. 480sparky

    480sparky Chief Free Electron Relocator Supporting Member

    Joined:
    Mar 8, 2011
    Messages:
    22,546
    Likes Received:
    8,088
    Location:
    Iowa
    Can others edit my Photos:
    Photos NOT OK to edit
    Well now. Aren't you just a little ray of sunshine this morning! :048:
     
  5. davidharmier60

    davidharmier60 No longer a newbie, moving up!

    Joined:
    Sep 9, 2017
    Messages:
    799
    Likes Received:
    213
    Chances are awfully good I will be but a mere memory in 20 Billion years....

    Sent from my SAMSUNG-SM-G890A using Tapatalk
     
  6. benhasajeep

    benhasajeep No longer a newbie, moving up!

    Top Poster Of Month

    Joined:
    May 4, 2006
    Messages:
    4,017
    Likes Received:
    494
    I will be in my estimated 250 millionth reincarnation at the time of the end. Wonder if I will be some bug smashed on the front of some spaceship riding around the universe by then???
     
  7. KmH

    KmH Helping photographers learn to fish Supporting Member

    Joined:
    Apr 9, 2009
    Messages:
    40,330
    Likes Received:
    5,506
    Location:
    Iowa
    Can others edit my Photos:
    Photos OK to edit
    How long a star spends on the Main Sequence depends mainly on how much mass a star forms with.
    Main-sequence stars are in hydrostatic equilibrium. In other words, outward thermal pressure from the hot core is balanced by the inward pressure of the gravity from all the mass above the core.

    New stars join the main sequence when they start fusing hydrogen into helium at their cores.
    Stars stay on the main sequence until there is no more hydrogen at the center of their cores to burn.

    The standard for 1 solar mass - M - is the mass of our sun.

    Those new to the main sequence stars having 0.5 M or less stay on the main sequence for way longer than our 1 M sun.
    Indeed some 77% of all stars have less than 0.5 M and most of them won't in late life evolve to be red giant stars.

    Stars experience mass loss as they age and evolve. The less massive stars evolve at a very much slower rate than stars having more than about 0.5 M.
    Stars having 1.5 M stay on the main sequence for only 1/3 as long as out sun, or about 3 billion years because of their faster evolution and mass loss.
    Stars twice that massive, or about 3 M only stay on the main sequence some 370 million years.
    10 M stars stay on the main sequence some 30 or so million years, and 60 M stars only stay on the main sequence some 3 million years.

    As mentioned in post #1 a bit more than 97% of all stars end their life as a white dwarf. The main reason being the mass they were born with.
    Any star having less than 1.44 M as it's late life mass (Chandrasekhar limit) becomes a white dwarf. As noted in post #1 in late life our sun will only have about 1/2 as much mass as it does today.

    It's the massive stars, in late life having more than 1.4 M☉, that become a neutron star or a black hole.
    Stars having a late life mass between 1.5 M and about 3 M becomes a neutron star, the more massive stars become black holes.

    Note that only about 1% of stars have more than 3 M while on the main sequence, and stars that late in life have remaining mass exceeding about 1.4 M are produced by stars that have over 5 or so M when on the main sequence.
     
  8. 480sparky

    480sparky Chief Free Electron Relocator Supporting Member

    Joined:
    Mar 8, 2011
    Messages:
    22,546
    Likes Received:
    8,088
    Location:
    Iowa
    Can others edit my Photos:
    Photos NOT OK to edit
    All the gold everyone has in thier pockets and made into jewelry was created long ago when an un-named star went nova. It ejected the gold it created into the stellar intermedium our solar system now occupies. This is the only natural process to create gold.

    So the shiny bling you wear is older than the sun, it's planets, the moon.......
     
  9. Gary A.

    Gary A. Been spending a lot of time on here!

    Joined:
    Sep 17, 2014
    Messages:
    18,661
    Likes Received:
    5,963
    Location:
    Southern California
    I love this stuff. But, I need to check your calculations though.
     
  10. Designer

    Designer Been spending a lot of time on here!

    Joined:
    Apr 13, 2012
    Messages:
    16,061
    Likes Received:
    4,018
    Location:
    Iowa
    Can others edit my Photos:
    Photos OK to edit
    Well, that and light is not particles. No such thing as "photons".
     
  11. snowbear

    snowbear Big Furball Supporting Member

    Joined:
    Dec 9, 2006
    Messages:
    12,773
    Likes Received:
    4,424
    Location:
    SoMD
    Can others edit my Photos:
    Photos OK to edit
    But light has characteristics of both waves and particles, at the same time. And it's speed (in a vacuum) is always the same, whether the source is moving or not, and if the source is moving, the speed of the light is the same regardless of the speed or direction of the source. Yep - light is some awesome stuff.
     
  12. KmH

    KmH Helping photographers learn to fish Supporting Member

    Joined:
    Apr 9, 2009
    Messages:
    40,330
    Likes Received:
    5,506
    Location:
    Iowa
    Can others edit my Photos:
    Photos OK to edit


    New info about how gold is made:
    GW170817 Press Release | LIGO Lab | Caltech


    Waveforms, and an audible chirp, from the 5 gravitational waves so far detected. The LVT signal was not conformed as a gravity wave detection. Each signal is GW for gravity wave and the date of the detection.
    The bottom waveform is from the neutron star merger and the audible chirp is heard at about 55 seconds near the end of the video.
     
    Last edited: Nov 17, 2017

Share This Page